| 摘要 |
PURPOSE: A method for forming an isolation layer is provided to be capable of preventing moat phenomenon at top edge portions of a trench. CONSTITUTION: A hard mask is formed on a semiconductor substrate(300) to cover an isolation region. The first trench is formed by etching the substrate. The first insulating spacer(313) and a conductive spacer(315) are sequentially formed at inner walls of the first trench. The second trench is then formed by using the hard mask and the first insulating spacer as a mask. An isolation layer(323) is formed by filling a gap-fill oxide layer and planarizing the gap-fill oxide layer to expose the hard mask. After removing the hard mask, the second insulating spacer(324) is formed at both sidewalls of the isolation layer(323).
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